I'm managing slices for quite a few clients, and one of them I've unfortunately had to resort to apache2 prefork because of php requirements and incompatibles with the weird assortment of software we had. (I had been running nginx/fastcgi, which was a dream from a memory usage standpoint but did weird stuff on certain pages.) We're bumping against a traffic ceiling due to our memory footprint, often having multi-minute slowdowns just because we can't keep up with the number of open connections. I've tuned the timeouts and keepalive settings as much as is reasonable, but we still have intermittent issues. We're about to launch some more php-powered stuff, but I'm reluctant to do it on the current slice because I know if we get any traffic it'll tank.

I'd love to flip to a 4 gig slice. I'd do it in a heartbeat if I could, but 4 gig slices don't support backups. Why, oh why don't 4 gig slices support backups? I don't need the extra drive space, I'm only using like 30 gig of space, and I could probably trim that if I needed to.